Sunday, 24 March 2013

Soviet 85 mm Guns vs Tigers

When the Germans encountered the thick armour of Matildas at Arras, they lowered their 88 mm FlaK guns and used them to engage the British tanks. When faced with the Tiger's thick armour, the Soviets did the same. The AA gun chosen for this task was the 85 mm anti-aircraft gun model 1939. Let's see how well it worked against a Tiger.

"Target: side. Distance: 800 m. Result: penetration, breach size 350 mm by 230 mm.
Target: side. Distance: 1450 m. Result: penetration, breach entrance diameter 110 mm, exit diameter 380 mm. A fragment 700 mm by 92 mm by 82 mm was knocked off. Cracks 220 mm, 200 mm, and 180 mm in length developed."


Some pretty catastrophic spalling going on here. Recall that the T-34-76 had to close in to 500 meters to even have a chance of damaging a Tiger tank, even from the side. 

"Target: side. Distance: 1450 meters. Result: penetration, breach diameter 115 mm.
Target: lower front. Distance: 1000 meters. Result: penetration. Entrance diameter 150 mm, exit diameter 160 mm. An armour fragment 230 mm in diameter broke off on the inside. Three cracks, 300 mm long, developed. The welding seam is destroyed." 



More catastrophic spalling, this time in the front. More welding seams giving in under pressure. The testers then got optimistic, and moved out to 1500 meters.

"Target: upper front. Distance: 1500 meters. Result: dent 30 mm deep, 120 mm in diameter. Bump on the inside.
Target: lower front. Distance: 1500 meters. Result: the plate cracked from previous impacts by the 85 mm gun. Two pieces broke off: 500 mm by 240 mm and 800 mm by 200 mm."


The Tiger's overhardened armour cracks and falls apart after two hits to the lower front plate. A bit disappointing for a tank that has been made out to be invincible. 

"Conclusion: the armour piercing shell can penetrate the side of the Tiger tank, 82 mm thick, from 1500 meters, and the front, 100 mm thick, from 1000 meters."

These are certainly some excellent results. They appear to be confirmed in practice, since a Red Army document on tactics of Tiger combat notes that it can be penetrated from the front at 1000 meters, and from the side at 1450 meters. It is not surprising that an 85 mm gun with similar ballistics was placed first in the SU-85, then in a T-34, to make a dangerous enemy for any German tank.

Now, let's take a look at tests against the Tiger II. The D-5 gun is used in these, mounted on the SU-85 tank destroyer.

"Shot # 22. Target: upper front plate. Distance: 300 m. Result: dent, 200 mm by 125 mm, 50 mm deep (including remains of the shell that welded itself to the armour). A fragment broke off the other side of the armour, 300 mm by 250 mm, 85 mm thick."

As with a lot of shots at the Tiger II, even when the shell does not penetrate, the spalling takes care of the crew and internal components anyway.

For shots from the side, the data is presented in a different report (from which there is only a table in the summary report). From that table, the following conclusions are made:

"The AP shell from the domestic gun D-5-S penetrates: 
  • the side of the hull from 1350 meters
  • the over-track hull from 800 meters
  • turret side from 800-1000 meters"
A T-34-85 fought several Tiger IIs from the s.Pz.Abt 501 at Ogledow. There were supposed to be 45 of these new tanks, but only 8 made the 45 km march. Oskin's T-34-85 destroyed 3 of the Tiger IIs in that battle. One of the tanks that was captured at Ogledow intact was the one that served as a test subject in the Tiger II penetration report. 

26 comments:

  1. All these shots appear to have been fired at 90°, whereas the Tiger's manual specifically asked their crews to position their hulls always at 45° during engagement

    ReplyDelete
    Replies
    1. Yes good point, but invalid. Note the distances, frontal penetration at a kilometre away, the Tiger crew would not know where the enemy was until the first shot, at which point they could take an educated guess depending on what part of the tank got hit. Even less likely that they could angle their armour to an enemy 1.35 metres away, especially if advancing.

      Delete
    2. I meant 1.35 miles away... oops.

      Delete
    3. The positioning of the tank happens before the first defensive shot is fired. They only get shots at the side armor after the tank has penetrated deep into the defensive formation. That is why there are Tigers and photos with dozens of non-effective hits on them. The many projectile ricocheting off with out interior effect, or spalling at all. I wish I could remember where I saw the one with almost 40 hits that was abandoned intact after running out of gas?

      Delete
    4. This adds nothing to the discussion. They were 40 85mm hits? 37mm? Or even 14.5mm ones? AP or HE? What was the distance?

      Delete
    5. The Tiger, being on the defensive most of the war, and having superior tactical awareness/visibility, will likely see the T34/85 first. It's the others that will get the Tiger. But even then the angle is rarely 0 degrees. Either horizontal or vertical. But the 85mm was effective enough.

      Delete
  2. it also seems that any tank with many many rounds fired into it is going to suffer a breakdown of armor. In normal battle conditions, a tank usually does not have so many 90 degree solid hits.

    ReplyDelete
    Replies
    1. Obviously, though in actual combat (heck, even in video game like Men of War), you would almost always need more than one shell to take out a tank. Even the 88 was documented (mentioned by Zinegata) to require at least 5 shots average to kill a tank, which translated into either, or all of the following -
      1. Poor accuracy
      2. Poor killing power
      3. Poor ability of the gun crew to acknowledge that the tank was disabled

      While the tests are faulty, they did what you should do against tanks - shoot at it until it burns or breaks apart.

      Delete
    2. http://photo.sbanzu.com/album/photos_m/36785_1025689_959d2.jpg

      Delete
  3. Is it possible to have a link/download for the whole report?

    ReplyDelete
    Replies
    1. http://www.mediafire.com/download.php?nt3c6r4c991z7uh

      http://www.mediafire.com/download.php?wo3q5irjuofexui

      Delete
    2. This comment has been removed by the author.

      Delete
  4. http://photo.sbanzu.com/album/photos_m/36785_1025689_959d2.jpg

    this is a picture of kubinka test to king tiger turret, shot #25 is from king tigers own cannon. it penetrated turret totally, from front to back. only gun which was able to do that..

    ReplyDelete
    Replies
    1. For the record, #23-25 (the ones in your photo) is translated here:
      http://tankarchives.blogspot.ca/2013/04/axis-guns-vs-german-tanks.html

      Delete
  5. poor russkies..look, your equipment was cheap and inferior, but you produced a lot of it...so, you won.period.

    ReplyDelete
    Replies
    1. Trannys don't apply to conversation about Russian tanks, period.

      "Betty Taylor
      Apr 6, 2015
      yes, im Transgendered."

      https://plus.google.com/116929067367877543146/posts?pid=6117760531781367362&oid=116929067367877543146



      Delete
    2. And Anonymous people are free to tell other Anonymous people to get over themselves! damn dude it's 2015
      anyone can comment, and if that is an issue i suggest you go drink a nice tall glass of STFU.....
      then maybe have a teaspoon of cement and toughen the hell up?
      cos if a person commenting on the web being trans is an issue for you you must be a soft weak person... you certainly need a bit more confidence in your sexual orientation... good luck with that! ;)

      Delete
    3. Betty, inferior equipment compared with what? Compare it with Brit and Yankee equipment, you will see which is inferior. If you want to compare it to German equipment, explain me why Germans avoided to expose their big kitties to Soviet heavy armored forces if they could.
      Soviet equipment was much cheaper, simple and more effective due to better planification and adjustment to requirements.
      After so much years it's amazing how tough could the propaganda be.

      Delete
    4. I'm refering to the big kitties of 1944-45.

      Delete
  6. I'd like to see a similar report of the 85 mm's performance vs a captured Panther.

    ReplyDelete
  7. Notice that all penetrations are at fairly long range = lower impact velocities.
    This is quite significant due to the use of uncapped, soft and low alloyed AP projectile steel which couldn´t be hardened to the levels required to withstand high impact velocity stress.

    The higher velocity 57mm could penetrate 82mm at long range, too, but failed to perforate 100mm at close range, where You´d expect it to penetrate much more.

    Thus, the soviet preference of increasing the calibre of gun (85mm instead of 57mm) appears to be a rational one, taking into account the fact that choices of projectile technology was lacking requirements to extract optimum performance.

    ReplyDelete
    Replies
    1. The Soviet 57 mm gun performed better than the British 6-pdr of the same caliber. Was their technology lacking too?

      Delete
  8. It doesn´t. The 6pdr outperforms the 57mm by a considerable margin at close range against both, vertical and inclined armour plate:

    APCBC vs vertical plate:
    0 yd distance: 125mm RHA (MQ)
    500 yd distance: 115mm RHA (MQ)
    1000 yd distance: 106mm RHA (MQ)
    2000 yd distance: 89mm RHA (MQ)

    APCBC vs 30° plate:
    0 yd distance: 100mm RHA (MQ)
    500 yd distance: 92mm RHA (MQ)
    1000 yd distance: 85mm RHA (MQ)
    2000 yd distance: 71mm RHA (MQ)

    The data reproduced here is from actual firing trials conducted during ww2 and was tabulated under "Comparison of thickness of plate perforated by full calibre and sub-calibre projectiles", p.68 SUPP 6/910 "The penetration of armour plate" (1950), originally classified as SECRET (declassified 1981).

    APDS and 2pdr/ 17pdr data omitted

    ReplyDelete
    Replies
    1. In Soviet trials, the ZiS-2 reliably penetrates the side of a Tiger at 1000 meters, the 6-pdr does not. The gun performs significantly worse than is claimed by your test.

      Delete
    2. Anonymous take in account British (USA and Germany also) used V50 tests, I don't remember it well what exactly Soviet used, but it was V70 or V80. This means two things, first Soviet used much harder and realistic tests. Second, you can't compare two different test made using different parameters in each one.

      Delete
    3. The criterium of penetration by definition in the 1950 british primary source was W/R complete penetration 50% probability criterium as used by the UK in late war contexts. This is comparable to US Navy ballistic limit. It is, however, not comparable to defintions in place in Germany or the SU.

      Germany never used a 50% criterium, and I don´t understant why this is going to be repeated here over and over again. The CIOS report "Steel AP and Theory of penetration" disprooves this myth. They used for explorative performance trial and service acceptance proof G(D), a close to 100% ballitic criterium (5 out of 5 successes for the calibre in question at narrow valicty range, no failures allowed), which is the most severe penetration definition used by any nation during ww2.

      The SU used both, a 20% and 80% criterium. However, if You calculate the mean of (V20+V80)/2 You get the british V50. Comparison thus, is possible.

      ZIS-2 does penetrate the side of a TIGER-I at 800m, exactly like the 6pdr. Tests at 1000m were not directed against the side of the tank but the commanders cast cupola.

      However, the ZIS-2 used inferior ammunition, and even while the 6pdr AP-shot was not excellent from the beginning, they subsequently improved the 6pdr APCBC throughout ww2. They used higher alloy steel, decremental hardening and improved caps and this allowed for improved penetration compared to the ZIS-2, particularely at shorter range /high muzzle velocity, where the 6pdr was superior to the ZIS-57 at virtually all obliquities.

      The performance at 800m was indifferent between both, as both perforated the TIGERs side but this doesn´t tell You anything about the problems encountered through shatter at elevated impact velocity close.
      ZIS-2 should be expected to completely perforate TIGER I front at close range with APC of average quality or even specially made, high alloyed AP but they failed because of inferior, uncapped, low alloyed and consequently soft projectiles which happened to strike beyond the velocity at which the projectile start to noticably deform.

      The problem is a general one for soviet ww2 AP projectiles as they were dismissive to the idea to shift to higher alloyed steel for projectiles and to cap them with armour piercing cap.

      There is nothing wrong with this rational but it predetermines to embark on a developmental trajectory favouring larger calibre, lower velocity gun systems over medium calibre, higher velocity gun systems.

      Delete